Mushroom pie (22-25cm | 8-9 inch mold)
- Sift the flour with the baking powder and salt, and crumb this mixture with the cold butter using a blender or your hands.
- Add the egg yolk and sour cream (one spoonful at a time, adding as needed) and knead the dough quickly.
- Roll into a ball and leave in the fridge for at least 1 hour.
- Roll out the dough on a lightly floured surface into a circle and put it into a mold.
- Flatten out the bottom and form high sides.
- Place in the fridge for 30 minutes.
- Fry the mushrooms and onion rings in the butter until golden.
- Season with salt and pepper, add the thyme, and leave to cool.
- Grate cheese on a coarse grater.
- Mix grated cheese, sour cream, eggs, salt, and pepper.
- Put half of the roasted mushrooms on the bottom of the base, pour the filling and place the rest of the mushrooms on top.
- Bake in a preheated to 356F | 180C oven until done (about 40 minutes). The middle of the pie should be firm, and the top should be browned. Serve warm or cold.